The strong development of nanotechnologies in the field of nanomedecine and nanoelectronics requires highly efficient luminescent nanocrystals for their use as nano-emitters or as nanoprobes for biological imaging, temperature sensing, etc. Among the different families of studied luminescent nanocrystals (Quantum Dots, dye-containing silica nanoparticles, etc), lanthanide-doped oxide nanocrystals present several advantages, such as their chemical stability in aqueous solution over time, their robustness towards optical excitation and their numerous optical transitions in the visible and near-infrared (NIR) range thanks to the presence of lanthanide ions.
Among the numerous synthesis methods developed to prepare nanometer-sized particles, I will focus on the solvothermal process and show its advantages to produce well-crystallized oxide nanocrystals. Based on the thermal decomposition of organo-metallic precursors at relatively low temperatures (< 500°C), under pressure, in a solvent, this synthesis takes place under those non-equilibrium conditions. The viscosity of the solvent decreases, increasing the mobility of the species and thus allowing the crystallization of phases that require generally high temperature to crystallize.
In my presentation I will detail our original synthesis technique and highlight the key parameters to obtain well-crystallized garnet nanocrystals of different sizes in the range 30 to 200 nm. I will discuss the optical efficiency of Ce3+-doped Y3Al5O12 (YAG) and Gd3Sc2Al3O12 (GSAG) nanocrystals, as nanophosphors for LED-based lighting applications. Moreover, I will report on the crystallinity and relative thermal sensitivity of NIR emitting Nd3+-doped GSAG:Nd3+ nanoparticles, as luminescence nanothermometers.
Biographie : Géraldine Dantelle obtained her PhD degree from the University Pierre et Marie Curie in Paris in 2006. After a post-doctoral stay at the University of Oxford, she joined the CNRS in 2009, where she develops her research on luminescent inorganic nanomaterials for various applications (biophotonics, solar cells, lighting). Her field of expertise lies from the material synthesis, shaping and functionalization to the structural and optical characterizations. She currently works at the Institut Néel (Grenoble), where she develops garnet-type nanocrystals as nanophosphors for white LED lighting, with the goal of producing eco-efficient devices. She also works on lanthanide-doped nanocrystals as nanoprobes for bio-imaging and thermal sensing.
